Refrigerating apparatus



Feb. 6, 1934. FEHR I 1,946,464

- REFRIGERATING APPARATUS Original Filed Nov. 20, 1930 2 SheetLs-Sh eet 1 "NE/2,24%) my i ATTORNEYS Feb. 6, 1934. R, FEHR 1,946,464

REFRIGERATING APPARATUS Original Filed Nov. 20, 1930 '2 Sheets-Sheet 2 lNVENTOR A I'TORNEYS Patented Feb. 6, 1934 "res PAT am ,oFF-ica REFRIGERAT NG APPARATUS John Ralph Fehr, Dayton, Ohio, assignor to Frigidaire Corporation, Dayton, Ohio, a corporation of Delaware Application November 20, 1930, Serial No. 496,903

Renewed June 8, 1933 18 Claims.

This invention relates to refrigerating apparatus and more particularly to control mechablanket of frost from becoming too thick, the

refrigerating element is permitted to warm for-a short period of time to allow this frost to melt off the refrigerating element. This is called defrosting.

It has been proposed to provide a control mechanism which will automatically provide a defrosting cycle or period at intervals, that is a period of time in which the refrigerating element warms so that the frost willmelt from the cooling unit. In domestic-refrigerators, provisions are ordinarily made for congealing comestibles and particularly for freezing ice cubes in trays which are supported within a portion of the cooling unit for this purpose. If a defrosting period should occur when it is desired to congeal comestibles or to freeze ice cubes, this congealing or freezing would be delayed. This delay would be objectionable if the congealed substances or the ice .cubes were desired within a short time.

' Accordingly one ofthe objects of my invention is to provide in a refrigerating system a signaling device for an automatic defrosting means which signaling mechanism will indicate the approach of a defrosting period so that the housewife is wamed in advance that a defrosting cycle or period will occur. r

Another object of the invention is to provide a means for resetting the automatic defrosting means so that the defrosting period may be made to occur at any selected time which is. desired.

A still further object of the invention is to provide a signaling device which is synchronized with an automatic defrosting means and to provide adjusting means so as to vary the relation between the defrosting period and the signaling period.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings: Fig. 1 represents a refrigerating system including a control mechanism and a refrigerator cabinet together with a diagrammatic illustration of the remaining elements of a refrigerating system;

Fig. 2 is a top view of the control mechanism; Fig. 3 is an enlarged view of a portion of the automatic defrosting and signalling mechanism, 90

and Fig. 4 is a section on the line 4-4 of Fig. 2.

The present invention is directed particularly to control mechanisms and contemplates an automatic defrosting means provided with a reset- 65 ting device and a signalling device having means adjustably connected to the automatic defrosting means for indicating the approach of the de frosting cycle. Referring to the drawings there is shown diagrammatically for illustrative purposes a refrigerating system of the compressor-condenser-expander type including a compressor 21 for compressing the refrigerant,preferably sulphur dioxide, and for forwarding it to the condenser 22 where it is liquefied and collected in the receiver'23. A supply conduit 26 conducts liquid refrigerant from the receiver 23 to the evaporator or refrigerating element 2'1 which is supported within the refrigerator cabinet 30 for cooling the food storage compartment 31 withi the cabinet. Theliquid'refrigerant within the coolingunit 27 vaporizes because of the absorption of heat from-the food storage compartment 31 and is returned to the compressor through the return conduit 28. The actuating mechanism for the compressor preferably comprises a motor 24 connected to the compressor by pulley and belt means 25. A switch means or control mechanism 29 is preferably'connected to the return conduit 28 for controlling the-motor 24 to provide alternate operating and idle periods of the compressor according to the pressure and consequently the temperature of the evaporator. The pressure responsive means of the control mechanism 29 comprises a metallic bellows 38 whichis sealed at the top and which is connected at the bottom by the conduit 32 to the return conduit 28 of the refrigerating system.

An operating lever 42 pivoted on ears 43 of. the 10 elevated platform 40 follows the movements of the Jaellows 38 by being connected thereto by a pin 44. A double lever 47 straddles the lever 42 and ispivoted thereto by the pin 52. One

end of the lever 47 is connected to one of the switch contacts 45 by a link 48. The cooperating switch contact 46 is mounted on the base 39 of the control mechanism. A snap action of the contact 45 with respect to the contact 46 is provided by a-camsystem which includes the hardened steel nose 49, fastened to the other end of the lever 47, against which a hardened steel roller 50 is biased by a carrier 51 and a spring 51a. When the lever 42 is in its lower position, the roller 50 rides upon the upper. portion of the nose 49 'and snaps the contacts 45 and 46 to the open position and when the lever 42 is in its upper position, the roller 50 rides upon movement of the lever 42 is resisted by a yieldable adjustable system comprising a coil spring carried within an adjustable casing 62 and bearing against a plunger 53 which acts against the extremity 63 of the lever. 42. when the pressure decreases and the bellows 38 collapses, the downward movement of the lever will be resisted by a coil spring 54 which surrounds a vertically threaded rod 56. This tension may be regulated by nuts 55 (see Fig. 4) carried on the vertically threaded rod 56 which is pivoted to lever 42 by a long pin 72. A balancing spring 57 adjusted by nut 58 is used on the opposite side of the base 39 of the devicejor resisting the tension of the spring 54.

The springs 54 and 57 and the resilient adjusting system comprises the plunger 53 and an adjustable cap 62 are provided for preferably so adjusting to produce what may be termed normal predetermined adjustment, that is for maintaining a pressure corresponding to a particular temperature which is ordinarily suitable for everyday operation of the refrigerator in which the system is used. The extremity 63 of the lever 42 bears against the plunger 53 only on the upward action of the lever 42. As the lever 42 begins to descend, the extremity 63 ceases to touch the plunger 53. Thus the plunger 53 affects the starting pressure but not the stopping pressure. The cap is therefore a starting adjustment.

This mechanism provides a normal cyclic operation of the refrigerating system, that is the compressor starts operating when a predetermined high pressure and temperature is reached in the evaporator, stops operating when a predetermined low pressure and temperature is reached, and remains idle until the predetermined high pressure and temperature is reached again. The temperature of the evaporator and food compartment varies, therefore between certain limits. but normally maintains a constant average temperature. The temperature provided by the mechanism thus described is sumcient to cool to the desired temperature the food thus stored in the usual compartment of the cabinet cooled by the cooling unit.

For various purposes it is often desired to de viate from the normal average temperature provided by the control mechanism. The devices for providing a temperature below the normal average temperature are ordinarily called cold control devices, while those providing a tempera. ture above the normal average temperature are usually called defrosting devices. The cold control devices ordinarily operate in such a manner that the temperature point, at which the compressor stops, is lowered to provide an average colder temperature for such a cycle, while in a defrosting device the temperature point at which the compressor starts may be raised. It will be seen that by providing an additional resilient pressure downwardly upon the movable end of the lever 42 a higher pressure within the bellows 38 will be necessary to move the lever 42 into its upper position in which the contacts 45 and 46 are closed. Such an additional resilient pressure will prolong the idle period of the compressor, and will allow the frost to melt from the cooling unit because of the resulting rise in temperature. By providing a resilient pressure upwardly upon the movable end of the lever 42, the compressor will operate longer and a colder average temperature will result.

Mounted upon the base 39 on the control mechanism but insulated therefrom by the insulating sheet is an automatic defrosting mechanism including a bent pawl 71 pivoted to the pin 72 and positioned so as to engage teeth upon the ratchet wheel 73 and thus cause the ratchet wheel to rotate intermittently because of the up and down movements of the lever 42. The ratchet wheel 73 is fixed upon a shaft 74 which is rotatably mounted and supported by the L- shaped standards 75 and 76 which are mounted upon the base 39 but insulated therefrom by the insulating sheet 70. Also fixed to the shaft 74, and mounted aside the ratchet wheel 73, is a defrosting cam 77 having a lobe 78 upon its periphery for producing the defrosting period. If desired, the cam 77 may be provided with a plurality of lobes similar to the lobe 78. A horizontal cam follower 79 is pivoted at an intermediate point to a pair of L-shaped supporting brackets 80 and 81 which are supported upon the base 39 of the control mechanism but insulated therefrom by the insulating strip 70. A nose 82 is formed upon one end of the cam follower 79 to coact with the lobe 78 upon the cam 77. On the other end of the cam follower 79, a leaf spring 83 is riveted which is of such a length so that its end will bear downwardly upon the projecting end 84 of the pin 52 which has been made particularly long for that purpose.

The .up and down movements of the lever 42, which are caused by the variation in pressure within the return conduit 28 and in the bellows 38, causes the pawl 71 to rotate the ratchet wheel counter clockwise a small amount at each down- 7.

ward movement of the lever 42. Once in each revolution the lobe 78 will. come around and engage the nose 82 of the cam follower 79, raising that end of the cam follower and thus lowering the opposite end of the cam follower '79 to which the leaf spring 83 is riveted and causing the end of the leaf spring 83 to bear down upon the extended end 84 of the pin 52 to reinforce the springs of the yieldable adjustable system which. resist the upward movement of the operating lever. This added reinforcement will make it necessary that a higher pressure be supplied to the bellows 38 before the switch contacts 45 and 46 close. This will cause a defrosting cycle or period, since a higher temperature in the evaporator will be required to supply a higher pressure to the bellows 38. During the defrosting cycle the evaporator 27 will become warm and the pressure within the evaporator 27 and the return conduit 28 will increase to a relatively higher pressure and after a time the pressure will be great enough to force the operating lever 42 upwardly, in spite of the added resistance of the spring 83, to cause the switch contacts 45 and 46 to close and thus start the electric motor 24 to operate the compressor 21 which then lowers the pressure withinthe evaporator 2'7 and return conduit 28 and forces liquid refrigerant into the evaporator 27. Upon the next downward move-. ment of the operating lever 42 the ratchet wheel 73 will be rotated so that the lobe 78 will be moved from disengagement with the nose 82 at the end of the follower 79. v

If desired, the teeth of the ratchet wheel'73 may be reversed and the end'of the pawl 71 altered in form so that the ratchet wheel '73 will be rotated in a clockwise direction upon the upward movement of the lever 42 instead of the downward movement. With the ratchet 73 and the pawl 71 arranged in this manner the lobe '78 and the nose at the end of the cam follower '79 will be disengaged upon the upward movement of the operating lever 42 at the end of the defrosting cycle.

According to the present invention, a signaling device is provided for indicating in advance the advent and duration of the defrosting cycle. The invention, however may be applied with equal facility to indicate any deviation from the normal average temperature. whether upwardly or downwardly. The mechanism which I prefer to employ includes a rotatable contact member 86 which is rotatably mounted upon the rotatable shaft 74 and which is provided with an arcuate slot 8'1 (see Fig. 3) through which an adjusting screw 88 projects and has its end threaded into the cam 77 for providing an adjustable means whereby the contact member 86 may be turned with respect to the cam member '17 and fastened by the adjusting screw 88 at any desired point because of the arcuate slot 87. The contact member 86 has a contact portion 89 which contacts with a cooperating spring contact member 90 fastened to but insulated from the foot of the L-shaped bracket 80. A movable auxiliary plate 99 pivoted upon the shaft 74, and fastened to the contact member 86 by a locking screw 100, is provided for varying the length of the contact portion. Y

Any suitable sort of signal may be used, if desired, but as my preferred embodiment I have chosen a signal light 91 having a distinguishing color which is shown supplied with current from the motor curcuit by the wires 92 and-93. The contact members 86 and 90 are connected in series with the wire 93 which is cutat an intermediate point and one of the resulting ends 94 is connected to the t-shaped standard '75 through which current is transmitted to'the shaft '74 and thus to the contact member 86, while the other end 95 is connected to contact member 90 which receives the current through the contact memvance of the defrosting period or cycle a period of time equal to the length of time ordinarily required to freeze or congeal the substance and also to keep the signal light lighted until the end of each defrosting cycle. With such an adjustment, if a substance is placed into the freezing compartment when the signalis not in action, there is an assurancethat the substance will be frozen. Preferably the signal light 91 is positioned at a suitable place, such as the ex-' terior of the refrigerator cabinet where it can be seen at all times, but if desired-the signal light may be positioned inside the cabinet so as to serve the double purpose of illumination and signalling. I 1

Means are also provided for resetting the defrosting cam so as to avoid the occurence of a defrosting cycle at an undersirable time, for instance, when it is desired to freeze ice cubes within the ice trays 96 supported within the cooling unit 27. To this end a crank 97 having a handle 98 thereon is connected to the end of the shaft '74 for rotating the shaft to reset the cam member '17 by rotating the lobe 78-of the cam '77 to a more desirable point. This will of course also set the contact portion 89 of the contact member 86 at a different position.

Thus it will be seen that I have provided a signaling device which is synchronized with an automatic defrosting means as well as adjusta refrigerating element positioned within the cabinet, control means for the refrigerating system including automatic defrosting means for providing defrosting periods of the refrigerating element, and signaling means for indicating in advance the advent of a defrosting period.

2. Refrigerating apparatus including a refrigerator cabinet, a refrigerating system including a refrigerating element positioned within the cabinet, control means for the'refrigerating system including automatic defrosting means for providing defrosting periods of the refrigerating element, signaling means for indicating in ad vance the advent of a defrosting Dfiriod, and means for resetting the automatic defrosting means.

3. Refrigerating apparatus including a refrigerator cabinet, a refrigerating system including a refrigerating element positioned within the cabinet, control means for the refrigerating system including automatic defrosting means for providing defrosting periods of the refrigerating element, and signaling means for indicating in advance the advent of .a defrosting period including a signal light positioned on an external portion of the cabinet.

4-. In a refrigerating apparatus the combination of a refrigerating system including a refrigcrating element, control means for the refrigerating system including automatic defrosting means for providing a plurality of intermittent defrosting periodsof the refrigerating element, and signaling means synchronized with the defrosting means for indicating in advance the advent of a defrosting period.

5. In arefrigerating apparatus, the combination of a refrigerating system including a refrigcrating element, control means for the refrigerating system including automatic defrosting means for providing a plurality of intermittent defrosting periods of the refrigerating element, signaling means synchronized with the defrosting means for indicating in advance the advent of a defrosting period, and means for varying the relationship between the defrosting means and the signaling means.

6. In a refrigerating apparatus, the combination of a refrigerating system including a cooling unit, control means for the refrigerating system having a movable member, rotatable means for providing intermittent defrosting periods of the cooling unit, means connected to the movable member for rotating the rotatable means, an electrically operated signaling device, and rotatablecontact means connected to the rotatable means for operating the signaling device.

7. In refrigerating apparatus, the combination of a refrigerating system including a refrigerating element, control means for the refrigerating system including automatic defrosting means for providing defrosting periods of the refrigerating element, signaling means for providing a signal ing period to indicate in advance the advent of a defrosting period, and means to vary the length of the signaling period.

8. In refrigerating apparatus, the combination of a refrigerating system including a refrigerating element, control means for the refrigerating system including automatic defrosting means for providing defrosting periods of the refrigerating element. signaling means for providing a signaling period to indicate in advance the advent of a defrosting period, and means to vary the dif ference in time between the beginning of the signaling period and the beginning of the defrosting period.

. 9. In refrigerating apparatus, the combination of a refrigerating system including a refrigerating element, control means for the refrigerating system including automatic defrosting means for providing defrosting periods of the refrigerating element, signaling means for providing a signaling period beginning in advance of the defrosting periods and ending at the end of the defrosting period for indicating in advance the advent of a defrosting period.

10. In refrigerating apparatus, the combination of a refrigerating system including a refrigerating element, control means for the refrigerating system to provide a normal average temperature of the refrigerating element, said control means including means for providing a temperature different from said normal temperature of the refrigerating element, and signaling means for indicating in advance the advent of any deviation from said normal average temperature of the refrigerating element.

11. In refrigerating apparatus, the combination of a refrigerating system including a refrigerating element, control means for the refrigerating system to provide normal cyclic operation of the system, said control means including means for providing a change from normal cyclic operation. and signaling means for indicating in advance the advent of any change from normal cyclic operation.

12. Refrigerating apparatus comprising in combination, a refrigerating system including a refrigerating element, control means for the refrigerating system including means operated automatically to cause defrosting periodsof said 1 frigerating system including means operated automatically to cause defrosting periods of said element, and signaling means for .indicating in advance the advent of a defrosting period, said signaling means being rendered effective automatically by the operations of the control means.

14. A refrigerating system, comprising in bombination, a cooling element normally maintained at desired refrigerating temperatures, means rendered operable automatically at intervals by the normal operation of the system for modifying from normal the temperature of the cooling element, and signaling means operated in accordance with the normal operations of the system for indicating in advance the advent of said modified temperature of the cooling element.

15. A refrigerating system, comprising in combination, a cooling element normally maintained at desired refrigerating temperatures, means rendered operable automatically at intervals by the normal operation of the system for increasing from normal the temperature of the cooling element, and signaling means operated in accordance with the normal operations of the system for indicating in advance the advent of said increase in temperature of the cooling element.

16. A refrigerating system including a cooling 110 element, control means for cyclically operating said system to maintain said cooling element at a temperature between certain predetermined limits, means rendered operable automatically at intervals by the normal cyclical operations of 1 5 said system for changing the temperature limit of said cooling element, and signaling means for indicating in advance the advent of a change in the temperature limit of the cooling element.

17. A refrigerating system including a cooling element, control means for cyclically operating said system. to maintain said cooling element at a temperature between a predetermined low limit and a predetermined high limit, means rendered operable automatically at intervals by the normal cyclical operations of said system for changing the high temperature limit of said cooling element while maintaining the low temperature limit 

